Screw press

Abstract

A screw press includes a ram, mounted for reciprocating movement relative to a press body, having a rotatably mounted threaded spindle extending therefrom, and a flywheel joined to the spindle for transmitting movement to the ram. The flywheel is driven by a friction disk which is arranged to engage the outer periphery of the flywheel, the disk being mounted on a shaft supported in the press body for rotational and axial movement relative to the body. When desired, the shaft can be axially moved to cause the disk to engage the flywheel, and an associated drive unit including a drive motor operates to rotatably drive the disk, thereby causing the ram to be moved within a work space in the press body. Preferably, one or more pairs of friction disks are arranged about the flywheel, each of the disks having an associated drive unit whereby the ram can be moved at different speeds and its direction reversed in accordance with the types of drive motors provided in the drive units.

What is claimed is: 
     
       1. A screw press comprising a press body, a ram mounted for reciprocating movement relative to said body, a threaded spindle extending from said ram for transmitting movement to said ram, a nut member mounted in said press body for supporting said spindle for rotational movement about the axis of said spindle and for moving said spindle in the axial direction thereof when said spindle is rotated, a flywheel coaxially joined to said spindle for transmitting rotational movement to said spindle, and a plurality in excess of two friction gear units arranged about the circumference of said flywheel for rotatably driving said flywheel, each of said friction gear units including a friction disk having its axis extending substantially perpendicular to the axis of said spindle so that said disk confronts the outer periphery of said flywheel, a shaft extending coaxially from said disk and supported by said press body for rotational and axial movement relative to said press body, wherein said disk is movable between a first position whereat said disk contacts the outer periphery of said flywheel to transmit rotational movement to said flywheel and a second position whereat said disk is moved away from said flywheel, means for moving each said disk toward said first position and means for moving each said disk toward said second position, and a drive unit supported by said press body for independently rotatably driving each said disk, said press body being arranged so that more than two of said friction gear units can be arranged at selected locations about the circumference of said flywheel to obtain desired movement of said ram when selected ones of said friction gear units are actuated to drive said flywheel. 
     
     
       2. A screw press according to claim 1, wherein said friction disk has a gear rim thereon, and said drive unit includes an electric motor having a pinion in meshed engagement with said gear rim. 
     
     
       3. A screw press according to claim 1, wherein said friction disk has a gear rigidly coupled to the side thereof facing away from said flywheel, and said drive unit includes an electric motor having a pinion in meshed engagement with said gear. 
     
     
       4. A screw press according to claim 2, wherein said gear rim is provided on the outer circumference of said friction disk. 
     
     
       5. A screw press according to claim 2, wherein said gear rim is formed in an inner region of and has a smaller diameter than said friction disk. 
     
     
       6. A screw press according to claim 1, wherein said press body includes a cylinder thereon and said friction disk shaft has a piston at the end thereof opposite said disk, said piston being arranged for axial movement within said cylinder. 
     
     
       7. A screw press according to claim 6, further including means associated with said cylinder for conveying a pressurized fluid for moving said piston to thereby move said disk. 
     
     
       8. A screw press according to claim 6 or 7, wherein said means for moving said disk toward said second position includes a return spring arranged between the side of said piston facing said disk and a portion of said press body. 
     
     
       9. A screw press according to claim 6, further including a stop screw arranged at one end of said cylinder for limiting the path of movement of said piston when said disk is moved toward said second position. 
     
     
       10. A screw press according to claim 1, wherein said press body includes a bearing for supporting said friction disk shaft for axial and rotational movement. 
     
     
       11. A screw press according to claim 1, wherein four said friction gear units are operatively arranged about the circumference of said flywheel. 
     
     
       12. A screw press according to claim 1, wherein at least six said friction gear units are operatively arranged about the circumference of said flywheel. 
     
     
       13. A screw press according to claim 11 or 12, wherein pairs of mutually opposed friction gear units are arranged to cooperate with each other. 
     
     
       14. A screw press according to claim 1, wherein one of said friction gear units is arranged to drive said flywheel at a rotational speed sufficiently slow and in either direction to enable said cam to be moved to a given position. 
     
     
       15. A screw press according to claim 14, wherein said one of said friction gear units includes a reversible motor having a sufficiently high gear ratio to enable said motor to drive said friction gear unit. 
     
     
       16. A screw press according to claim 14, wherein said one of said friction gear units includes two motors which are alternately actuated to drive a common shaft, one of said motors being arranged as a secondary motor and having a higher gear ratio relative to the other motor. 
     
     
       17. A screw press according to claim 14, wherein said one of said friction gear units includes a reversible pole electric motor having a sufficiently high number of poles to enable said motor to drive said friction gear unit. 
     
     
       18. A screw press comprising a press body, a ram mounted for reciprocating movement relative to said body, a threaded spindle extending from said ram for transmitting movement to said ram, a nut member mounted in said press body for supporting said spindle for rotational movement about the axis of said spindle and for moving said spindle in the axial direction thereof when said spindle is rotated, a flywheel coaxially joined to said spindle for transmitting rotational movement to said spindle, and at least two friction gear units arranged about the circumference of said flywheel for rotatably driving said flywheel, each of said friction gear units including a friction disk having its axis extending substantially perpendicular to the axis of said spindle so that said disk confronts the outer periphery of said flywheel, a disk shaft extending coaxially from said disk and supported by said press body for rotational and axial movement relative to said press body, wherein said disk is movable between a first position whereat said disk contacts the outer periphery of said flywheel to transmit rotational movement to said flywheel and a second position whereat said disk is moved away from said flywheel, means for moving said friction disk toward said first position and means for moving said disk toward said second position, and a drive unit supported by said press body for rotatably driving said disk, said drive unit of one of said friction gear units including a common drive shaft and two motors which are arranged to be alternately actuated to drive said common drive shaft, one of said motors being arranged as a secondary motor and having a higher gear ratio relative to the other motor to drive said flywheel at a rotational speed sufficiently slow and in either direction to enable said ram to be moved to a given position.